Power module packaging with dual side cooling

Abstract

A multichip package includes a first semiconductor device mounted on a first leadframe, in which a primary heat producing surface of the first semiconductor device is oriented towards and in contact with a heat dispersing region of the first leadframe. A second semiconductor device is mounted on a second leadframe, in which a primary heat producing surface of the second semiconductor device is oriented towards and in contact with a heat dispersing region of the second leadframe. A surface of the heat dispersing region of the first leadframe is exposed on a first side of the multichip package, and a surface of the heat dispersing region of the second leadframe is exposed on a second side of the multichip package that is opposite from the first side.

What is claimed is: 
     
       1. A multichip package comprising:
 a first semiconductor device mounted on a first leadframe, in which a primary heat producing surface of the first semiconductor device is oriented towards and in contact with a heat dispersing region of the first leadframe; 
 a second semiconductor device mounted on a second leadframe, in which a primary heat producing surface of the second semiconductor device is oriented towards and in contact with a heat dispersing region of the second leadframe; 
 in which the first leadframe is a coplanar etched leadframe with protruding contact regions, and the second leadframe is a coplanar etched leadframe with protruding contact regions in contact with corresponding protruding contact regions on the first leadframe; and 
 in which a surface of the heat dispersing region of the first leadframe is exposed on a first side of the multichip package, and a surface of the heat dispersing region of the second leadframe is exposed on a second side of the multichip package that is opposite from the first side. 
 
     
     
       2. The device of  claim 1 , further including mold material encapsulating the first semiconductor device and the second semiconductor device such that the surface of the heat dispersing surface of the heat sink region of the first leadframe and the surface of the heat dispersing region of the second leadframe remain exposed. 
     
     
       3. The device of  claim 2 , further including a third semiconductor device interconnected to the first semiconductor device and to the second semiconductor device by the first leadframe and the second leadframe and encapsulated by the mold material. 
     
     
       4. The device of  claim 2 , further including a heat sink connected to the heat dispersing region of the second leadframe. 
     
     
       5. A method for making a multichip package, the method comprising:
 fabricating an upper leadframe having a heat dispersing region and a lower leadframe having a heat dispersing region by etching a sheet of conductive material; 
 attaching a first side of a first chip to the heat dispersing region of the lower leadframe; 
 attaching a first side of a second chip to the heat dispersing region of the upper leadframe; 
 superimposing the upper lead frame over the lower leadframe such that a second side of the first chip is attached to the heat dispersing region of the second leadframe and a second side of the second chip is attached to the heat dispersing region of the first leadframe to form an assembly; and 
 encapsulating the assembly with mold compound such that a surface of the heat dispersing region of the upper leadframe and a surface of the heat dispersing region of the lower leadframe are exposed. 
 
     
     
       6. A multichip package comprising:
 a first semiconductor device mounted on a first leadframe, in which a drain region of the first semiconductor device is oriented towards and in contact with a heat dispersing region of the first leadframe, and in which a source region of the first semiconductor device is oriented towards and in contact with a second leadframe; 
 a second semiconductor device mounted on the second leadframe, in which a drain region of the second semiconductor device is oriented towards and in contact with a heat dispersing region of the second leadframe and in which a source region of the second semiconductor device is oriented towards and in contact with the first leadframe; and 
 in which a surface of the heat dispersing region of the first leadframe is exposed on a first side of the multichip package, and a surface of the heat dispersing region of the second leadframe is exposed on a second side of the multichip package that is opposite from the first side. 
 
     
     
       7. The multichip package of  claim 6 , in which the first leadframe is a coplanar etched leadframe with protruding contact regions, and the second leadframe is a coplanar etched leadframe with protruding contact regions in contact with corresponding protruding contact regions on the first leadframe. 
     
     
       8. The multichip package of  claim 6 , in which the first leadframe is a coplanar stamped leadframe with protruding contact regions, and the second leadframe is a coplanar stamped leadframe with protruding contact regions in contact with corresponding protruding contact regions on the first leadframe. 
     
     
       9. The device of  claim 6 , further including mold material encapsulating the first semiconductor device and the second semiconductor device such that the surface of the heat dispersing surface of the heat sink region of the first leadframe and the surface of the heat dispersing region of the second leadframe remain exposed. 
     
     
       10. The device of  claim 9 , further including a third semiconductor device interconnected to the first semiconductor device and to the second semiconductor device by the first leadframe and the second leadframe and encapsulated by the mold material. 
     
     
       11. The device of  claim 6 , in which the first semiconductor device and the second semiconductor device are both vertical power MOSFET (metal oxide semiconductor field-effect transistor) devices.